
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>

#include "api_sm4.h"


static const uint8_t SBOX[256] = {
	0xD6, 0x90, 0xE9, 0xFE, 0xCC, 0xE1, 0x3D, 0xB7, 0x16, 0xB6, 0x14, 0xC2,
	0x28, 0xFB, 0x2C, 0x05, 0x2B, 0x67, 0x9A, 0x76, 0x2A, 0xBE, 0x04, 0xC3,
	0xAA, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99, 0x9C, 0x42, 0x50, 0xF4,
	0x91, 0xEF, 0x98, 0x7A, 0x33, 0x54, 0x0B, 0x43, 0xED, 0xCF, 0xAC, 0x62,
	0xE4, 0xB3, 0x1C, 0xA9, 0xC9, 0x08, 0xE8, 0x95, 0x80, 0xDF, 0x94, 0xFA,
	0x75, 0x8F, 0x3F, 0xA6, 0x47, 0x07, 0xA7, 0xFC, 0xF3, 0x73, 0x17, 0xBA,
	0x83, 0x59, 0x3C, 0x19, 0xE6, 0x85, 0x4F, 0xA8, 0x68, 0x6B, 0x81, 0xB2,
	0x71, 0x64, 0xDA, 0x8B, 0xF8, 0xEB, 0x0F, 0x4B, 0x70, 0x56, 0x9D, 0x35,
	0x1E, 0x24, 0x0E, 0x5E, 0x63, 0x58, 0xD1, 0xA2, 0x25, 0x22, 0x7C, 0x3B,
	0x01, 0x21, 0x78, 0x87, 0xD4, 0x00, 0x46, 0x57, 0x9F, 0xD3, 0x27, 0x52,
	0x4C, 0x36, 0x02, 0xE7, 0xA0, 0xC4, 0xC8, 0x9E, 0xEA, 0xBF, 0x8A, 0xD2,
	0x40, 0xC7, 0x38, 0xB5, 0xA3, 0xF7, 0xF2, 0xCE, 0xF9, 0x61, 0x15, 0xA1,
	0xE0, 0xAE, 0x5D, 0xA4, 0x9B, 0x34, 0x1A, 0x55, 0xAD, 0x93, 0x32, 0x30,
	0xF5, 0x8C, 0xB1, 0xE3, 0x1D, 0xF6, 0xE2, 0x2E, 0x82, 0x66, 0xCA, 0x60,
	0xC0, 0x29, 0x23, 0xAB, 0x0D, 0x53, 0x4E, 0x6F, 0xD5, 0xDB, 0x37, 0x45,
	0xDE, 0xFD, 0x8E, 0x2F, 0x03, 0xFF, 0x6A, 0x72, 0x6D, 0x6C, 0x5B, 0x51,
	0x8D, 0x1B, 0xAF, 0x92, 0xBB, 0xDD, 0xBC, 0x7F, 0x11, 0xD9, 0x5C, 0x41,
	0x1F, 0x10, 0x5A, 0xD8, 0x0A, 0xC1, 0x31, 0x88, 0xA5, 0xCD, 0x7B, 0xBD,
	0x2D, 0x74, 0xD0, 0x12, 0xB8, 0xE5, 0xB4, 0xB0, 0x89, 0x69, 0x97, 0x4A,
	0x0C, 0x96, 0x77, 0x7E, 0x65, 0xB9, 0xF1, 0x09, 0xC5, 0x6E, 0xC6, 0x84,
	0x18, 0xF0, 0x7D, 0xEC, 0x3A, 0xDC, 0x4D, 0x20, 0x79, 0xEE, 0x5F, 0x3E,
	0xD7, 0xCB, 0x39, 0x48
};

static const uint32_t FK [ 4] = {
    0xA3B1BAC6, 0x56AA3350, 0x677D9197, 0xB27022DC
};

static const uint32_t CK [32] = {
    0x00070E15, 0x1C232A31, 0x383F464D, 0x545B6269, 0x70777E85, 0x8C939AA1,
    0xA8AFB6BD, 0xC4CBD2D9, 0xE0E7EEF5, 0xFC030A11, 0x181F262D, 0x343B4249,
    0x50575E65, 0x6C737A81, 0x888F969D, 0xA4ABB2B9, 0xC0C7CED5, 0xDCE3EAF1,
    0xF8FF060D, 0x141B2229, 0x30373E45, 0x4C535A61, 0x686F767D, 0x848B9299,
    0xA0A7AEB5, 0xBCC3CAD1, 0xD8DFE6ED, 0xF4FB0209, 0x10171E25, 0x2C333A41,
    0x484F565D, 0x646B7279
};

#define ROL32(X,Y) ((X<<Y) | (X >> (32-Y)))

#define TAU(A) (((uint32_t)SBOX[(A >> 24) & 0xFF] << 24) | \
                ((uint32_t)SBOX[(A >> 16) & 0xFF] << 16) | \
                ((uint32_t)SBOX[(A >>  8) & 0xFF] <<  8) | \
                ((uint32_t)SBOX[(A >>  0) & 0xFF] <<  0) ) \

static inline uint32_t T(uint32_t X) {
    uint32_t x1 = TAU(X);
    uint32_t x2 = x1 ^ ROL32(x1, 2) ^ ROL32(x1,10) ^
                       ROL32(x1,18) ^ ROL32(x1,24) ;
    return   x2;
}

static inline uint32_t Tp(uint32_t X) {
    uint32_t x1 = TAU(X);
    uint32_t x2 = x1 ^ ROL32(x1,13) ^ ROL32(x1,23);
    return   x2;
}

void    sm4_key_schedule_enc_ref (
    uint32_t rk [32], //!< Output expanded round key
    uint8_t  mk [16]  //!< Input cipher key
) {
    uint32_t * mkp = (uint32_t*)mk;
    uint32_t * rkp = (uint32_t*)rk;
    uint32_t * ckp = (uint32_t*)CK;
    uint32_t * rke = (uint32_t*)rk + 32;

    uint32_t K0 = __builtin_bswap32(mkp[0]) ^ FK[0];
    uint32_t K1 = __builtin_bswap32(mkp[1]) ^ FK[1];
    uint32_t K2 = __builtin_bswap32(mkp[2]) ^ FK[2];
    uint32_t K3 = __builtin_bswap32(mkp[3]) ^ FK[3];

    uint32_t t  ;

    while(rkp < rke) {

        t  = K1 ^ K2 ^ K3 ^ ckp[0];
        K0 = K0 ^ Tp(t);

        K1 = K1 ^ Tp(K2 ^ K3 ^ K0 ^ ckp[1]);
        K2 = K2 ^ Tp(K3 ^ K0 ^ K1 ^ ckp[2]);
        K3 = K3 ^ Tp(K0 ^ K1 ^ K2 ^ ckp[3]);

        rkp[0] = K0;
        rkp[1] = K1;
        rkp[2] = K2;
        rkp[3] = K3;

        rkp     += 4;
        ckp     += 4;
    }

}


void    sm4_key_schedule_dec_ref (
    uint32_t rk [32], //!< Output expanded round key
    uint8_t  mk [16]  //!< Input cipher key
){

    uint32_t tmp;

    sm4_key_schedule_enc_ref(rk, mk);

    for(int i = 0; i < 16; i ++) {
        tmp      = rk[   i];
        rk[   i] = rk[31-i];
        rk[31-i] = tmp     ;
    }

}


void    sm4_block_enc_dec_ref (
    uint8_t  out [16], // Output block
    uint8_t  in  [16], // Input block
    uint32_t rk  [32]  // Round key (encrypt or decrypt)
){

    uint32_t * inp = (uint32_t*)in      ;
    uint32_t * op  = (uint32_t*)out     ;
    uint32_t * rkp = (uint32_t*)rk      ;
    uint32_t * rke = (uint32_t*)rk + 32 ;

    uint32_t   X0  = __builtin_bswap32(inp[0]);
    uint32_t   X1  = __builtin_bswap32(inp[1]);
    uint32_t   X2  = __builtin_bswap32(inp[2]);
    uint32_t   X3  = __builtin_bswap32(inp[3]);

    while(rkp < rke) {

        X0   = X0 ^ T(X1 ^ X2 ^ X3 ^ rkp[0]);
        X1   = X1 ^ T(X2 ^ X3 ^ X0 ^ rkp[1]);
        X2   = X2 ^ T(X3 ^ X0 ^ X1 ^ rkp[2]);
        X3   = X3 ^ T(X0 ^ X1 ^ X2 ^ rkp[3]);

        rkp += 4;
    }

    op[0] = __builtin_bswap32(X3);
    op[1] = __builtin_bswap32(X2);
    op[2] = __builtin_bswap32(X1);
    op[3] = __builtin_bswap32(X0);

}

